1. Field
The present invention relates to a method and apparatus to control a focal length of a curved reflector in real time.
2. Description of the Related Art
A conventional heliostat can be a conventional curved reflector that is pivoted as the sun moves to focus light from a light source, such as the sun onto a target such as a tower. The energy from the conventional heliostat is then collected at the tower and converted into usable energy which is stored for later use. However, the conventional curved reflector usually only pivots in response to the movement of the light source. This is problematic because as the light source moves, the location of the focal point may change. That is, the focal point is usually located at a focal length away from the curved reflector. However, the movement of the light source usually changes the focal length. Thus, the light that is reflected from the conventional curved reflector may be focused at an area that is closer than the tower, or further away than the tower. This is undesirable because the focused energy is wasted if it is focused closer or further away than the tower.
Thus, there is a need for a method and apparatus to control a focal length of a curved reflector in real time.